AIH BATTERIES

1. Large Format Aqueous Electrolyte Polyionic Devices
for Low Cost, Multi-Hour Stationary Energy Storage
J.F. Whitacre1,2, T Wiley2, S. Shanbhag2, S. Chun1, W. Yang2, D. Blackwood2, A. Mohamed,1,2 E. Weber2,
D. Humphreys2
1 Carnegie Mellon University, Department of Materials Science and Engineering, Department of Engineering and Public
Policy, 5000 Forbes Ave, Pittsburgh PA 15213
2 Aquion Energy ,32 39th Street, Pittsburgh PA 15201

2. © Aquion Energy, Inc. www.aquionenergy.com 2
Aquion Energy - Leading Energy Storage Provider
PRODUCT
+ 48V stack and
module building
blocks
+ Scalable to 1000 Vdc
and multi-MWh
installations
+ Battery Monitoring
only, no active
management
required
COMPANY
+ Spun out of Carnegie
Mellon in 2010
+ HQ in Pittsburgh, PA
+ Investors include
Kleiner Perkins,
Foundation Capital,
Bill Gates, ATV
+ History of solid
execution
MANUFACTURING
+ 350,000 sq ft facility
in Pennsylvania
+ State-of-the-art
manufacturing line in
place & operational
+ Shipping product to
customers globally
+ Aqueous Hybrid Ion
(AHI) intercalation
battery system
+ Invented by Aquion
+ Optimized for long
duration (4+ hr) and
very high cycle life
+ Cost-effective, safe,
and sustainable
TECHNOLOGY

3. © Aquion Energy, Inc. 3
The Economic Reality of Microgrid Energy Storage
+ Defining metric: Levelized cost of stored energy (LCOSE) as
amortized over the lifetime of the system
Useable
discharge
capacity
Delivered
energy on
discharge

4. © Aquion Energy, Inc. 4
The Economic Reality of Microgrid Energy Storage
+ Another key - cycle life:
• Issue: typically energy density and cycle life are inversely correlated
+ Assuming we must have a have a LCOSE of < $0.1/kWh
+ Then we need > 5000 cycles
+ Price point of under $300/(usable kWh installed)

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The Economic Reality of Energy Storage
Must use:
+ Cheap materials (<$4/kg),
+ Simple manufacturing approach
(“borrowed technologies”)

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Solution: Low Cost and Sufficient Enough Energy Density
+ Goal was to identify the “sweet spot” between specific cost, energy density,
and cycle life
+ Significant testing yielded a finding:
• Aqueous electrolyte sodium ion functional materials and battery structures
• If you set aside energy density as requirement, using neutral pH electrolyte allow
for very substantial cost savings, and benign electrode reactions

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– +
Aqueous Hybrid Ion (AHI™) Chemistry
Aqueous Electrolyte:
+ Water-based, ambient
temperature, sodium
sulfate electrolyte.
Hybrid Reactions:
+ An asymmetric/hybrid
electrode configuration:
• Cathode: Intercalation reaction
• Anode: Pseudocapacitive and
intercalation interaction
Multiple Ions:
+ The chemistry uses sodium
and lithium ions as the
primary charge carrier to
store energy inside the
battery.
+ ANODE: Carbon composite with pseudocapacitive and
intercalation reactions
+ ELECTROLYTE: Na2SO4 in an aqueous solution
+ CATHODE: Manganese Oxide spinel structure
hosts intercalation reaction
+ SEPARATOR: Non-woven cellulosic material

8. © Aquion Energy, Inc. Proprietary and Confidential. 8
Building Block: Internal Contents and Structure
Building a battery that is high-performing, safe,
sustainable and cost-effective using abundant,
nontoxic materials.
+ CARBON
+ SALTWATER
+ BASE OXIDE
+ COTTON
Carbon Composite Anode
Synthetic Cotton Separator
Manganese Oxide Cathode
Sodium Sulfate Electrolyte

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Stability/Capacity of First Generation Chemistry
+ Na4Mn9O18 Cathode Material
+ Significant energy present,
+ BUT, using costing rules, materials have to be under $2/kg all in to compete
+ Very difficult to do!

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Cycle Life/Columbic Efficiency
+ 1000 cycles, negligible loss in capacity, ~100% Columbic efficiency
Capacity(mAh)
5 C charge/discharge rate

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Lambda MnO2 in Na2SO4
+ λ – MnO2 has over 2 times the capacity and 3 times the energy of Na4Mn9O18
+ Rate capability also found to be very good

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Second Generation Chemistry: Lambda-MnO2
+ Much higher specific capacity compared to Na4Mn9O18
+ In balanced device, over 100 Wh/kg (cathode) at lower rates
+ Still extremely stable
+ Added cost of using Li2CO3 to template material is justified.

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The Anode: Activated Carbon in Neutral PH
+ Over 200 F/g can be had from carbons derived from simple carbohydrates
+ Over 120 F/g can be gained from low cost (<$2/kg) carbons derived from
woods
Dextrose - based Coconut/wood - based

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Polyionic Functionality
+ 3 different species are functional:
• Lithium – cathode materials templating, extracted into electrolyte during
first charge, remains functional
• Sodium – electrolyte cation, intercalates into MnO2 of cathode and also
performs EDLC function at anode
• and Hydrogen. . . .

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Anodic Pourbaix Shift at Anode Enables High Cell V
+ At the anode: as the potential of hydrogen evolution is reached, local OH- species are generated, and are not
extracted rapidly
+ This increases the pH inside the negative electrode, and subsequently re-stabilizes the local water. There is
also the natural overpotential of water splitting on Carbon
+ So minimum stable anode potential is -0.9 V (vs. NHE) at local pH of 14 plus ~0.2 to 0.4 V of over potential.
+ If cathode is pinned at ~+1 V, then, we have a cell voltage of over 2 V
+ BUT hydrogen is evolved during this process – what of it?
AC
Vmax
*Nature Chemistry, 2, 2010, pg 760
*

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Three-Electrode Data:
+ There is excess cathode material to pin the positive electrode potential
below the point of oxygen evolution

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Making it Practical: Electrode Thickness
+ In thin format cells, the material displays excellent rate capability, excellent
round trip energy efficiency.
+ However, these cells are far too costly to scale with these dimensions . . .

18. © Aquion Energy, Inc. 18
MnO2-based cells: Energy Density
+ Na functional in cubic spinel - different recipe is optimal
+ >40 Wh/kg specific capacity, same long term stability
+ > 80% round trip energy efficiency

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Manufacturing Process and Flow
+ Established, low-cost, and proven manufacturing processes
Blend Granulate Pelletize
ANODE
CATHODE
Battery
Assembly
+ Container
+ Separator
+ Conductor
+ Lid
Electrolyte
Infiltration Qualify

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Flexible, Scalable Energy Storage
AHIPRODUCTS
Racked Module-Based Systems
SYSTEMCONFIGURATIONS
M-Line Battery Modules
+ 25.5 kWh
+ Nominal 48V output
+ Designed for industry-
standard racking
+ Forklift-ready
S-Line Battery Stacks
+ 2.4 kWh
+ Nominal 48V output
+ Smallest product
increment
Stack-Based Systems

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Aquion S-Line Battery Stack
+ Smallest product increment
+ Eight batteries in series, fused at the stack level
+ Nominal 48V output
+ Designed for low cost, performance, and modularity
OPERATION & PERFORMANCE
Nominal Energy 2.4 kWh at 20 hour discharge,
30° C
Cycle Life >3,000 cycles at 100% DoD*
Operating Temp Range** -5 to 40° C
Round Trip DC Efficiency >85% at 20 hour discharge, 30° C
Voltage Range 30 to 59 V
Charge/Discharge Modes CC, CP, CV, AC ripple tolerant
PHYSICAL CHARACTERISTICS
Height 935 mm 36.8 in
Width 330 mm 13.0 in
Depth 310 mm 12.2 in
Weight 113 kg 249 lbs
* Cycle life to 80% retained capacity
** 40° C average ambient over 24 hours

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Performance: Cycle Life
+/- 4A cycling on large format battery; typical voltage response

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Performance: Cycle Life
+ 100’s of deep cycles on full stack
product
+ Verified by 3rd party testing
+ 0ver 3000 cycles on small format
lab units (with known leaks in cell)
+ Fully stable to at least 40˚ C
Lab Cell: >2500 cycles and counting
Battery level data, 40˚C,
100% DoD, +/-4A cycling
Stack level data, 50%
DoD, +/- 4A cycling, 24˚C

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Abuse Tolerance: Partial State of Charge
+ Aquion’s batteries can stand at partial state of charge with no significant
degradation
Pulse: The batteries are cycled between 45-55% SOC using 10A. Two full cycles are run every 1000 pulses.
Data from Aquion S10 Battery Stack

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Large Format System Cycle Stability: PSOC Test
+ 4000 Partial State of Charge Swings executed on full stack at 40˚C
+ Batteries in string are well balanced
+ Similar unit currently at Sandia ASAP for identical testing

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Large Format System Cycle Stability: 40˚C PSOC Test
+ Reference Cycle Discharge Voltage vs.
Capacity Data
30
35
40
45
50
0 5 10 15 20 25 30 35
ref 1 (no CV hold in charge)
ref 2 after 1000 pulses
ref 3 after 1850 pulses
ref 4 after 2850 pulses
ref 5 after 3850 pulses
Voltage(V)
Discharge capacity (Ah)
0
200
400
600
800
1000
1200
1400
0 1000 2000 3000 4000
Dischargeenergyat4A Cycle Number
+ Reference Cycle Energy vs. Cycle #
The 4 A constant current discharge reference cycle shows more capacity after the
1000 cycles than before (slightly different charge regime used, but comparison is
indicative of no degradation), and no change after 4000 PSOC cycles

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Application Specific Duty Profile; Power vs Time
+ Off grid zero diesel solar/battery hybrid; provided by Optimal Power
Solutions
Profile altered to give specific energy flow/efficiency:
1,400 Wh processed each cycle at 83% efficiency

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StackVoltage(V)
Applications Testing: PV/Battery Hybrid
+ 70 cycles logged of 90% DoD swing
+ 24 hour cycle
+ Excellent stability observed
+ NO loss in capacity delivered
+ NO drift in stack voltage over time
+ NO self balancing needed
+ Test ongoing
+ Tester shutdown/restart on day 44 caused
brief overcharge; stack unaffected.

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Applications Testing: PV/Battery Hybrid
+ Left plot: 2A 100% DoD reference cycle after 70+ days of cycling; excellent
capacity documented after significant use.
+ Right plot: voltage and current as a function of time after resuming cycling
after reference test
• V increasing; unit is significantly more efficient than 80%

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Current Internal Demos
12 S-Line Stacks, Off-grid Demo
+ Off-grid 20’ shipping container simulating a telecom installation
+ Online since April 2013
+ Off the shelf solar and electronics
+ 12 energy storage stacks, 48V
+ Capable of 2 kW continuous load
+ Demonstrated interoperability :
14 M-Line Modules, Grid-tied Demo (In Progress)
+ 168 battery stacks configured into 14 modules
+ ~270 kWh at 20 hour discharge
+ Testing with several PCS providers
+ Operational as of Q214
+ Collaboration with global leading power electronic firms:

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Summary
+ Augmented electrode chemistry results in very appealing voltage swing, cost
proposition.
+ Full scale manufacturing plant is on line; product shipping to customers
globally
+ Multiple test beds have been assembled and are in use
• Including a DoE funded 14 Module test stand
• Strong data generated to verify product claims
+ Long term test results, systems-level show that this product is ready for
market insertion

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Thank you
+ Contact us to learn more about how our AHI™ technology for your
application:
• www.aquionenergy.com
• 412.904.6400